The proposed research project will investigate means for inducing immunity to lower respiratory tract disease caused by nontypable Haemophilus influenzae. This bacterial organism is an important cause of both tracheobronchitis and pneumonia in elderly or debilitated persons, and especially affects people with chronic obstructive pulmonary disease. Monoclonal antibody technology will be employed to determine which surface antigens of nontypable H. influenzae are worthy of further investigation as potential vaccine candidates. Both the outer membrane proteins and lipopolysaccharide of this organism will be evaluated for their abilities to serve as targets for protective antibodies which enhance pulmonary clearance of this pathogen. An animal model system will be employed to measure the effect of both active and passive immunization regimens on pulmonary clearance rates. Purified surface antigens of nontypable H. influenzae will be evaluated for their abilities to induce the synthesis of antibodies which enhance pulmonary clearance of nontypable H. influenzae. Protective surface antigens which bear antigenic determinants common to or cross-reactive with most or all strains of nontypable H. influenzae will be identified through the use of monoclonal antibody technology.